The present invention relates generally to foundry apparatus and more specifically to mechanism for the production of foundry sand molds. The invention is more specifically directed toward a device which utilizes a pressurized medium for compression of the molding sand about the pattern device from which the mold is to be formed.
In the prior art, and more specifically in a process known from German DAS No. 1,961,234, a certain amount of compressed air issuing from a compressed air tank arranged above a molding box acts briefly upon a batch of mold forming sand poured loosely over a pattern plate in a molding box to compress the sand, with the air passing through outflow openings in the pattern plate.
Processes of this type involve the disadvantage that the portion of the molding sand which is admitted directly by the compressed air is compressed more forcefully than the portion bearing upon the pattern arrangement.
Accordingly, the invention is directed toward providing apparatus whereby molding sand may be optimally compressed in the formation of a foundry sand mold. The optimum compression of the molding sand may be achieved independently of the individual pattern parts and maximum compression of the molding sand batch can be effected on all surfaces which will be brought into contact with a casting melt, as well as the mold parting surface, with the compression decreasing from the mold parting plane to the exterior of the mold.